1. Field of the Invention
The present invention relates in general to video information processing, and more specifically to a system and method of video decoding with error detection and concealment.
2. Description of the Related Art
Video capability is becoming more prevalent for mobile devices. Such mobile devices, however, usually rely on wireless communications through a wireless channel, which is often an error prone channel. In an error prone channel, visual quality degradation occurs because of an error-corrupted bitstream. The corrupted bitstream may heavily degrade the visual quality of any one or more individual frames or pictures. In certain configurations the corrupted bitstream may cause extra false or fake frames which degrades visual quality and results in audio/visual (A/V) synchronization problems. As an example, errors at the bit level in a video slice may cause the video decoder to erroneously interpret the next slice of a current frame to be a first slice of a new frame. As a result, a frame containing multiple slices may be mistakenly decoded as multiple fake frames. Multiple fake frames may occur, for example, in video decoders operating according to the International Telecommunication Union (ITU) H.264 standard, otherwise known as the Advanced Video Coding (AVC) standard, which is Part 10 of MPEG-4 (Motion Picture Experts Group). In general, multiple fake frames may occur in any standard in which a video slice header incorporating a frame number (FN) and/or a picture order count (POC) is corrupted.
Certain video standards do not provide for error correction or concealment in the event of a corrupted bitstream. In some configurations, for example, corrupted video slices are simply discarded resulting in significant visual degradation. Instead of dropping the video slice, attempts have been made to correct or conceal the damaged slice. Scene change detection may be considered for correction or concealment attempts. Most scene change detection algorithms, however, suffer from high computational complexity, which is particularly problematic for mobile devices with limited computational capacity. Conventional error concealment often results in serious visual deterioration, especially when during a scene change. In the case of a scene change, some intraframe encoded video blocks have been decoded as interframe or skip video blocks due to bit-errors within the video block. If these fake non-intraframe encoded video blocks are concealed with temporal information, a seriously degraded cut-and-paste picture is often produced, and subsequent pictures are further deteriorated due to motion compensation using the wrong information, such as a previous frame that was part of a different scene.